The present invention relates generally to projectile shields, and, more specifically, to a projectile shield usable, for example, in a blade containment structure for a gas turbine engine which is effective for absorbing energy and containing projectiles hurled upon damage to rotating parts.
Gas turbine engines include rotating blades which, if broken, become projectiles which are hurled radially outwardly from the engine. Blade containment structures may be used as a shield for containing such projectiles and thereby reducing damage to the engine and to the aircraft supporting the engine.
Conventional blade containment structures include, for example, metal, resin impregnated glass fiber, carbon fiber, ballistic nylon, glass fiber tape, or aromatic polyamide fibers such as Kevlar, or other ballistic strands which may be provided in layers for increasing the energy absorbing capability of containment structure.
Woven ballistic strands especially without the use of a resin matrix, have a known disadvantage in that individual strands tend to be pushed apart by a projectile upon impact which allows the projectile to more readily penetrate the woven ballistic fabric. Accordingly many layers of such fabric are typically provided to ensure that a projectile of predetermined energy is unable to pass through all the layers of the ballistic fabric.